Effect of EGFP gene transfection on the cell cycle distribution of primary cultured human chondrocytes

AIM: To investigate the effect of enhanced green fluorescence protein (EGFP) gene transfection on the cell cycle distribution of primary cultured human chondrocytes in order to establish a tracking method of cultured human nasoseptal chondrocytes. METHODS: pEGFP-N1 plasmid was amplified in E.coli, and purified by high purity kit. Primary cultured human chondrocytes,which were initially obtained from the nasoseptal cartilage, were cultured in vitro and transferred with pEGFP-N1 by means of electroporation with Amaxa nucleofector device. Transfering process and transient expression were evaluated by laser scanning confocal microscope (LSCM), the transfer efficiency and the cell cycle distribution were evaluated by flow cytometry. RESULTS: There was significant expression of EGFP at 24 h after transferring. The transfection efficiency of pEGFP-N1 into primary cultured human chondrocytes reached 35.37％ at 48 h. It didn't affect the process of cell adherance and had no effect on the cell cycle distribution. CONCLUSION: Primary cultured human chondrocytes, which were transfected with pEGFP, are alive in vitro, and the transferring process doesn't affect the cell cycle distribution. These results suggest that pEGFP-N1 is an ideal transient expression vector for primary cultured human chondrocytes and it might be a well tracer in construction tissue engineered cartilage.     

Meiotic competence of mouse oocytes reconstructed by replacing the germinal vesicle with a male pronucleus and somatic nucleus

The present study examines the contribution of the nucleus to meiotic competence in mouse oocytes that were reconstructed using nuclear transfer. Three types of reconstructed oocytes were produced: MP‐GV, by transplanting the male pronucleus (MP) into germinal vesicle (GV) stage oocytes; 3T3‐GV, by transplanting the nucleus of a National Institute of Health (NIH) 3T3 cell into a GV stage oocyte; and 3T3‐MII, by transplanting the nucleus of an NIH 3T3 cell into a metaphase II (MII) stage oocyte. The fusion rates differed, but not significantly, in the MP‐GV, 3T3‐GV, and 3T3‐MII groups (77, 63, 56%, respectively). Then, meiotic competence was compared in MP‐GV, 3T3‐GV and non‐manipulated GV stage oocytes as a control. Nuclear envelope breakdown occurred in all the reconstructed oocytes, as well as the control ones. The percentage of first polar body extrusion differed between the MP‐GV (100%), 3T3‐GV (72%), and control (67%) groups. DNA staining with Hoechst 33342 revealed that in the MP‐GV‐group oocytes that had reached MII stage, the chromosomes were condensed and aligned in a regular array similar to the normal metaphase plate. By contrast, in 3T3‐GV group oocytes, the condensed chromosomes were irregularly scattered in the cytoplasm. These results suggest that the donor nucleus affects meiotic competence in reconstructed oocytes.     

Significance of local immunity in hen reproductive organs

The current paper describes aspects of local immunity in the ovary and oviduct, and the significance of immunity to reproductive functions in hens. The immunocompetent cell populations in the ovary and oviduct change with a positive correlation to sexual activity, and gonadal steroid is one of the key factors in the increase. Local immune responses mediated by major histocompatibility complex class II and T cell subsets occur in response to infection by Salmonella enteritidis, which may contaminate eggs. In the ovary, immunocompetent cells are also suggested to play roles in the regulation of ovarian functions. Macrophages and T cells are likely to enhance the regression of atretic follicles to maintain the ovarian tissue microenvironment. Autoantibodies to ovarian tissues appeared in the hens with low egg laying frequency, suggesting that the auto‐antibodies may be one of the factors in the decline of egg production. In the oviduct, local immunity possibly has a role in the selection of sperm, though the immunoreactions may also affect sperm survival leading to the decline in fertility. The concentration of yolk IgY, which plays a role in maternal immunity transmission, significantly decreases with the aging of birds, whereas it is significantly increased by estrogen. Therefore, the immune system plays significant roles not only in defense against infection, but also in the functions of reproductive organs. Investigations on the local immune system in the reproductive organs and factors affecting it are of importance for the production of sterile eggs and improvement of reproductive functions.     

母牛一胎双犊技术的研究

选择9头母牛先行人工授精、7天后再移植冷冻胚胎以生产双犊。试验结果表明,母牛产双犊达44.44%(P<0.01)。提示:采用A(I人工授精)+ET(胚胎移植)是提高母牛双犊率的有效技术措施之一。     

Transgenerational epigenetic variance for body weight in meat quails

We aimed to estimate transgenerational epigenetic variance for body weight using genealogical and phenotypic information in meat quails. Animals were individually weighted from 1 week after hatching, with weight records at 7, 14, 21, 28, 35 and 42 days of age (BW7, BW14, BW21, BW28, BW35 and BW42, respectively). Single‐trait genetic analyses were performed using mixed models with random epigenetic effects. Variance components were estimated by the restricted maximum likelihood method. A grid search for values of autorecursive parameter (λ) ranging from 0 to 0.5 was used in the variance component estimation. This parameter is directly related to the reset coefficient (ν) and the epigenetic coefficient of transmissibility (1‐ν). The epigenetic effect was only significant for BW7. Direct heritability estimates for body weight ranged in magnitude (from 0.15 to 0.26), with the highest estimate for BW7. Epigenetic heritability was 0.10 for BW7, and close to zero for the other body weights. The inclusion of the epigenetic effect in the model helped to explain the residual and non‐Mendelian variability of initial body weight in meat quails.     

中国东北和华北地区紫花苜蓿根瘤菌遗传多样性研究

【目的】紫花苜蓿(Medicago sativa L.)被誉为牧草之王,近年来,中国东北和华北地区种植面积不断扩大,但紫花苜蓿质量与产量仍不足以满足中国畜牧业发展的需求。本研究旨在分析中国东北和华北地区紫花苜蓿根瘤菌遗传多样性,为紫花苜蓿高效固氮根瘤菌的筛选与应用提供参考。【方法】采用表面消毒和平板划线法从根瘤中分离纯化根瘤菌单菌落;使用BOX-PCR方法对供试菌株进行基因型划分;选取代表菌株进行持家基因(atpD、glnII和rpoB)和共生基因(nifH和nodC)的系统发育分析。【结果】从中国东北和华北19个采样地共分离纯化了499株根瘤菌,BOX-PCR可将供试菌株分为37种BOX型,BOX型存在显著的地理分布现象,同时寄主品种对根瘤菌基因型具有一定的选择作用。97.60%(487/499)的根瘤菌为Sinorhizobium meliloti。其余12株分别为S. adhaerens、Mesorhizobium huakuii、Rhizobium loessense、R.mesosinicum、R. vignae、Mesorhizobium sp.和Phyllobacteri...     

基于多时相双极化SAR数据的作物种植面积提取

及时准确地获取农作物的空间分布信息和种植面积,在农业生产管理与农业政策的制定等斱面具有非常重要的作用。本文以多时相Sentinel-1A影像(4月17日、5月5日、6月16日、7月22日、8月27日、9月2日)为主要数据源,根据研究区作物的物候特征,提取棉花、玉米和果树在不同生长期的后向散射系数(Sigma)和归一化后向散射系数(Gamma)。通过对作物不同极化、不同时相后向散射系数的统计,建立散射特征时序变化曲线,幵分析其特征。利用人工神经网络(Artificial neural network)、支持向量机(Support vector machine)和随机森林(Random forest) 3种分类斱法对研究区的主要农作物迚行分类识别以及种植面积提取,幵对分类结果对比分析和验证。结果表明, 1)棉花的后向散射系数在6月现蕾期和7月开花期明显上升,8月仹达最高值,变化特征最明显,易与其他作物区分;玉米和果树的后向散射系数在9月仹与其他地物之间表现出显著差异。2)相较于神经网络和支持向量机,随机森林的分类效果最好,总体精度达88.97%。其中,对棉花和果园的分类精度为90.88%和...     

不同覆盖方式对旱作马铃薯生长及土壤水热特征的影响

【目的】探讨不同覆盖方式对西北旱作区农田土壤水热和马铃薯生长的影响。【方法】2015—2016年连续2年设置沟垄地膜全覆盖(DD)、沟垄地膜半覆盖(DB)和沟垄二元覆盖(DJ)3种覆盖方式大田试验,以平作不覆盖为对照(CK),研究不同覆盖方式下土壤水温变异特征及对马铃薯生长及块茎形成的影响。【结果】覆盖处理全生育期0—200 cm土层土壤含水量均高于CK,DJ处理在播后70—90 d土壤保水效果最佳。覆盖能降低0—200 cm土层土壤水分变异系数,以DJ处理的土壤水分垂直稳定性最强。与CK相比,DD处理在播后30—50 d的0—15 cm土层土壤增温效果显著,而DJ处理在全生育期0—25 cm土层土壤温度表现"降温和增温双重效应"。各覆盖处理能降低0—25 cm土层土壤温度变异系数,以DJ处理最小,其土壤温度垂直稳定性最强。覆盖能提高马铃薯出苗率和影响出苗天数,其中DD处理平均出苗天数较CK提前4.5 d,而DJ处理推迟3.5 d。马铃薯生育期生物量累积动态变化符合Logistic生长模型,以DJ处理生物量理论值和生长速率最大,快速生长持续期最长。通过主成分分析发现,除马铃薯生物量、单...     

河西走廊永昌县农地流转行为及影响因素研究

为了社会的稳定和土地利用率的提高,国家出台了"三权分置"政策来促进土地流转.以永昌县为例,利用计量统计模型研究了农户农地流转行为及影响因素,以期为政府政策制定提供依据.研究结果表明:(1)样本区农地流转意愿强,农地流转率达79.61％;(2)户均农地流转规模较小,转出规模小于0.30 hm2的户数占78.14％,转入规...